Articles of footwear generally include an upper and a sole structure.
An upper generally forms a footwear body that extends over a portion of a foot to retain the article of footwear on the foot. An upper may extend over an instep and toe areas of the foot, along medial and lateral sides of the foot, and/or around a heel area of the foot. An upper may be formed from one or more material elements, such as textiles, polymer sheet layers, foam layers, leather, synthetic leather, and other materials. These materials may be attached together, such as by stitching or adhesive bonding. An upper may be configured to form an interior of the footwear that comfortably and securely receives a foot. An upper may include an opening that facilitates entry and removal of the foot from the interior of the upper, and further may include a closure system, such as lacing, cinches, or straps, that enables a wearer to adjust a fit of the article of footwear.
A sole structure generally is attached to the upper and disposed between the foot and a ground surface. For example, a sole structure may be attached to a lower portion of the upper. A sole structure may include one or more components, including one or more outsole, midsole, insole, insert, bladder or fluid-filled chamber, such as an airbag. A sole structure also may include other components or elements, such as ground surface traction elements.
An upper and sole structure may operate to provide a comfortable article of footwear structure configured to benefit a wearer engaged in any of a variety of activities. For example, a sole structure may operate to attenuate impact and ground reaction forces and/or to provide traction on a ground surface. An upper and sole structure may cooperate to control various foot motions, such as pronation.